1. Field of the Invention
The present invention relates to a method for preparing manganese sulfate and zinc sulfate from waste batteries containing manganese and zinc, and more particularly to such a method for preparing manganese sulfate and zinc sulfate from waste batteries containing manganese and zinc, the method comprising adding zinc powder and activated carbon to a leached solution obtained from a continuous leaching process so as to remove heavy metals (nickel and cadmium) and organic materials from the leached solution, and then spray-drying the leached solution to simultaneously obtain manganese sulfate and zinc sulfate.
2. Background of the Related Art
Manganese batteries and alkaline manganese batteries have been excluded from burden charge-imposed items and have been treated as general wastes while having come into the market since 1996. However, since these batteries contain metal components such as manganese, zinc, iron and the like and an electrolyte such as KOH and the like, they give a load to the surrounding environment upon the reclamation or incineration thereof. Therefore, the developed countries such as the European Unit (EU), etc., have an obligation to collect and recycle all the waste batteries including primary batteries.
Recently, in the situation where the costs of mineral resources and metals rise due to a serious disturbance in the raw material market, in the case where batteries employing high-purity metals and metal compounds are recycled, the recycling of waste batteries is indispensable, but not optional for Korea depending upon the import of all of its metal minerals in terms of storage of the raw materials.
In Korea, currently, manganese batteries and alkaline manganese batteries are treated as general wastes. Since constituent components of the batteries are mostly low-priced metals, no battery manufacturer positively recycles waste manganese batteries.
Even in foreign countries, the recycling of the manganese batteries and the alkaline manganese batteries is recognized in terms of resolution of environmental problems rather than recovery of priced metals. The manganese batteries and the alkaline manganese batteries are generally treated by using a dry treatment method in which they are supplied as raw materials in a ferromanganese preparing process. But such a dry treatment method entails a problem in that the price of the prepared products including collection and conveyance costs is relatively low as compared to treatment costs, leading to a decrease in economic efficiency.
In order to address and resolve the above problem, a research is in progress on the development of a waste battery recycling process with economic efficiency. Since the waste batteries are not generated in a large amount, the research progresses toward wet treatment or high value addition of the waste batteries.
As a technique of covering and recycling priced metals from waste batteries, Korean Patent Registration No. 656,891 discloses a method for preparing a manganese (Mn)-zinc (Zn) ferrite powder from waste manganese batteries, which includes a three time leaching process consisting of alkaline leaching, acid leaching and coprecipitation for the purpose of recovery of zinc. However, the above method implies a drawback in that it requires complicated processes such as separate injection of manganese, zinc and iron so as to obtain the Mn—Zn ferrite powder, addition of an alkaline leaching solution used in recovery of zinc for the adjustment of the pH, etc.